Magneto-Stark Effect of Excitons as the Origin of Second Harmonic Generation in ZnO
Magneto-Stark Effect of Excitons as the Origin of Second Harmonic Generation in ZnO
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DOI：
10.1103/physrevlett.110.116402
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发表时间：
2013-03-12
影响因子：
8.6
通讯作者：
Bayer, M.
中科院分区：
文献类型：
--
作者：
Lafrentz, M.;Brunne, D.;Bayer, M.
激子的磁斯塔克效应被证明是一个有效的来源，在六角氧化锌的光学非线性。在2s和2 p激子的光谱范围内，观察到由外磁场诱导的强共振二次谐波产生信号。微观理论分析表明，对于有限波矢的激子，相反宇称的激子态被混合的有效奇宇称电场诱导的磁场，尽管它的偶宇称。二次谐波产生强度的场、光谱和偏振依赖性验证了所提出的机制。观察到的现象并不局限于某个对称类，因此必须在其他半导体中有效。DOI：10.1103/PhysRevLett.110.116402
The magneto-Stark effect of excitons is demonstrated to be an efficient source of optical nonlinearity in hexagonal ZnO. Strong resonant second harmonic generation signals induced by an external magnetic field are observed in the spectral range of 2s and 2p excitons. The microscopic theoretical analysis shows that for excitons with a finite wave vector, exciton states of opposite parity are mixed by an effective odd parity electric field induced by the magnetic field despite its even parity. The field, spectral, and polarization dependencies of the second harmonic generation intensity validate the proposed mechanism. The observed phenomenon is not limited to a certain symmetry class and therefore must be effective in other semiconductors. DOI: 10.1103/PhysRevLett.110.116402